Light emitting diodes (LEDs) are expected to the source of light for the next generation lighting which will replace incandescent bulbs and fluourescent lights. White light and other color LEDs will be essential for different applications. At present, LED chips emit light centered around one wavelength, which would be considered monochromatic. Multiple colors including white are only generated by assembling several LEDs of different colors or by second step excitation. For example, white light an be generated by mixing red, green and blue, or using blue to excite yellow phosphor in order to generate white light.